Lepidoptera of Thailand This article contents the list of the 4414 Thai Lepidoptera of 73 families, based upon the info-system of the Cesa with some illustrations during the field notes of the authors in the northern provinces of this country. The expeditions were realized privately in the years of 2005 and 2006 and a report on this survey was published online in 2007 The authors published several articles and reports on their activities in South East Asia, including Thailand. In 2007, a comprehensive report on the Cesa projects was published. The present article deals especially with the list of the Thai Lepidoptera, arranged by the first author. Illustrations and faunal information during the field studies belong to the second author. In the following paper, the scientific names of the species are arranged under the alphabetically listed families known in Thailand. Synonymous names are given in chronological order. Range of each species is explained as codes and in dark blue in colour. If previously published image of the second author exists, the necessary citation is given within the related species. Listed 73 families are as follows; Acraeidae, Adelidae, Aganaidae, Amathusiidae, Arctiidae, Argynnidae, Blastobasidae, Bombycidae, Brachodidae, Brahmaeidae, Callidulidae, Carposinidae, Choreutidae, Cosmopterigidae, Cossidae, Ctenuchidae, Cyclidiidae, Cyclotornidae, Danaidae, Drepanidae, Epermeniidae, Eriocottidae, Ethmiidae, Eupterotidae, Gelechiidae, Geometridae, Glyphipterygidae, Gracillariidae, Hepialidae, Hesperiidae, Himantopteridae, Hyblaeidae, Immidae, Lacturidae, Lasiocampidae, Lecithoceridae, Libytheidae, Limacodidae, Lycaenidae, Lymantriidae, Lyonetiidae, Metarbelidae, Micronoctuidae, Nepticulidae, Mirinidae, Noctuidae, Notodontidae, Oecophoridae, Opostegidae, Palaeosetidae, Papilionidae, Pieridae, Psychidae, Pterophoridae, Pyralidae, Riodinidae, Roeslerstammiidae, Saturniidae, Satyridae, Scythridae, Sesiidae, Sphingidae, Stathmopodidae, Stenomidae, Thaumetopoeidae, Thyatiridae, Thyridae, Tineidae, Tortricidae, Uraniidae, Xyloryctidae, Yponomeutidae, Zygaenidae.